A small library of 3’-deoxy-C3’-substituted xylofuranosyl-pyrimidine nucleoside analogues were prepared by photoinduced thiol-ene addition of various thiols, including normal and branched alkyl-, 2-hydroxyethyl, benzyl-, and sugar thiols, to 3’-exomethylene derivatives of 2’,5’-di-O-tert-butyldimethylsilyl-protected ribothymidine and uridine. The bioactivity of these derivatives was studied on tumorous SCC (mouse squamous carcinoma cell) and immortalized control HaCaT (human keratinocyte) cell lines. Several alkyl-substituted analogues elicited promising cytostatic activity in low micromolar concentrations with a slight selectivity toward tumor cells. Near-infrared live-cell imaging revealed SCC tumor cell-specific mitotic blockade via genotoxicity of analogue 10, bearing an n-butyl side chain. This analogue essentially affects the chromatin structure of SCC tumor cells, inducing a condensed nuclear material and micronuclei as also supported by fluorescent microscopy. The results highlight that thiol-ene chemistry represents an efficient strategy to discover novel nucleoside analogues with non-natural sugar structures as anticancer agents.

The toxicity of gadolinium is reduced by chelating agents that render this heavy metal into contrast complexes used for medical magnetic resonance imaging. However, the dissociation of gadolinium chelates is known to generate Gd ions, the cellular toxicity of which has not been tested in details. The cytotoxic effects of Gd(III) ions were evaluated by monitoring the proliferation, measuring the cellular motility and following chromatin changes in various cell lines upon Gd treatment. Measurements applied long-term scanning microscopy and a perfusion platform that replaced the medium with test solutions, bypassed physical contact with the cell culture during experiments, and provided uninterrupted high time-resolution time-lapse photomicrography for an extended period of time. Genotoxicity specific chromatin changes characteristic to Gd(III) were distinguished in human skin keratinocytes (HaCaT), human limbal stem cells (HuLi), colorectal adenocarcinoma (CaCO), murine squamous carcinoma (SCC) and Indian muntjac (IM) cell lines. Characteristic features of Gd(III) toxicity were: loss of cellular motility, irreversible attachment of cells to the growth surface and cell death. Injury-specific chromatin changes manifested at micromolar Gd concentrations as premature chromatin condensation and highly condensed sticky chromatin patches. Gd(III) concentration- and cell type-dependent reduction of normal adherence, as well as premature chromatin condensation confirmed apoptosis. The risk related to the release of toxic Gd ions from gadolinium complexes and their effects on mono- and multi-layer cellular barriers have to be reconsidered when these chelated complexes are used as contrasting agents especially in relation to possible blood-brain barrier damages.

Background/Aim: Conventional viability tests, help to screen the cellular effects of candidate molecules, but the endpoint of these measurements lacks sufficient information regarding the molecular aspects. A non-invasive, easy-to-setup live-cell microscopic method served to in-depth analysis of mechanisms of potential anticancer drugs. Materials and Methods: The proposed method combining the -2,5-diphenyltetrazolium bromide) test with time-lapse scanning microscopy (TLS), provided additional data related to the cell-cycle and the dynamic properties of cell morphology. Apoptotic and necrotic events became detectable with these methods. Results: Quantification of the results was assisted by image analysis of the acquired image sequences. After demonstrating the potential of the TLS method, a series of experiments compared the in vitro effect of a known and a newly synthesized nucleoside analogue. Conclusion: The proposed approach provided a more in-depth insight into the cellular processes that can be affected by known chemotherapeutic agents including nucleoside analogues rather than applying repeated individual treatments.

The performance of domestic agriculture and the food industry is constantly increasing. Demand for food is growing on the global market, with domestic food export growing by 10% in 2019. However, there are still reserves in exploiting the growth path and transforming it into income. Efficiency, revenue and profit growth of each product line depends on numerous factors; one of the key tools being the monitoring of the production process, getting to know the production environment accurately, data collecting, database building, development of applications that support automated interventions and decisions, and integration the above tools. The fundamental objective goal of the presented research is to approach the research of maize pollen cells as an agriculturally relevant model organism from a new direction, the long-term (Time-Lapse System) microscopic study of the growth dynamics of the pollen germ tube. In the scope of the research, two industrially and agriculturally important aspects taken into account, which also detected digitally: the growth of the maize pollen germ tube and the viability of the pollen. The research can provide a basis for the more accurate understanding and subsequent study of the effects of different biotic and abiotic stress factors on pollen growth, and may open up new possibilities in the field of digital agricultural biotechnology.

We have established earlier a cell line from the human limbal area to study cell growth and response to the toxic effects of antibiotics used in ophthalmology. In the recent work, the effect of multi-walled carbon nanotubes (MWCNTs) in cornea damage was investigated in vitro and in vivo in mice. In the in vitro experiments, the physiological effects of multi-walled carbon nano-tube (MWCNT) bundles on corneal wound healing were mimicked in vitro by a reepithelization limbal stem cell model. Murine in vivo experiments were performed with intact, non-functionalized MWCNTs to confirm the validity of in vitro tests. The MWCNTs of 10 -30 nm outer diameter at low concentration (5 µg/ml) did not interfere with the wound healing of the damaged limbal cell monolayer. Higher than 50 µg/ml concentrations: a) generated MWCNT aggregates, b) restrained the movement and prolonged the time of wound healing, c) increased the amplitudes of the oscillations of the cells, and d) resulted in scar formation affecting both cor-neal function and refraction. Chromatin condensation, a sensitive test of the viability of cells, including limbal stem cells revealed that the presence of a low concentration of nanotubes (5 µg/ml), did not significantly affect the viability of limbal cells. Chromatin condensation was completed and metaphase chromosomes were seen at higher MWCNT concentration proving that their aggregates did not affect the viability of limbal cells. This concentration of MWCNTs (5 µg/ml) did impact neither the reepithelization in vitro nor in vivo in the scratched eyes of mice. Scar formation took place at higher than 50 µg/ml concentrations and the healing of the cornea was prevented by the lack of movement of increasingly larger macroaggregates. In vivo murine experiments vali-dated in vitro monolayer regrowth followed by time-lapse microscopy portraying realistically the reepithelization of the damaged cornea that process was gradually slowed down by macro aggregate formation and caused the scarring of the cornea.